Quelle  prestera_counter.c   Sprache: C

// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/* Copyright (c) 2021 Marvell International Ltd. All rights reserved */

#include "prestera.h"
#include "prestera_hw.h"
#include "prestera_acl.h"
#include "prestera_counter.h"

#define COUNTER_POLL_TIME (msecs_to_jiffies(1000))
#define COUNTER_RESCHED_TIME (msecs_to_jiffies(50))
#define COUNTER_BULK_SIZE (256)

struct prestera_counter {
 struct prestera_switch *sw;
 struct delayed_work stats_dw;
 struct mutex mtx;  /* protect block_list */
 struct prestera_counter_block **block_list;
 u32 total_read;
 u32 block_list_len;
 u32 curr_idx;
 bool is_fetching;
};

struct prestera_counter_block {
 struct list_head list;
 u32 id;
 u32 offset;
 u32 num_counters;
 u32 client;
 struct idr counter_idr;
 refcount_t refcnt;
 struct mutex mtx;  /* protect stats and counter_idr */
 struct prestera_counter_stats *stats;
 u8 *counter_flag;
 bool is_updating;
 bool full;
};

enum {
 COUNTER_FLAG_READY = 0,
 COUNTER_FLAG_INVALID = 1
};

static bool
prestera_counter_is_ready(struct prestera_counter_block *block, u32 id)
{
 return block->counter_flag[id - block->offset] == COUNTER_FLAG_READY;
}

static void prestera_counter_lock(struct prestera_counter *counter)
{
 mutex_lock(&counter->mtx);
}

static void prestera_counter_unlock(struct prestera_counter *counter)
{
 mutex_unlock(&counter->mtx);
}

static void prestera_counter_block_lock(struct prestera_counter_block *block)
{
 mutex_lock(&block->mtx);
}

static void prestera_counter_block_unlock(struct prestera_counter_block *block)
{
 mutex_unlock(&block->mtx);
}

static bool prestera_counter_block_incref(struct prestera_counter_block *block)
{
 return refcount_inc_not_zero(&block->refcnt);
}

static bool prestera_counter_block_decref(struct prestera_counter_block *block)
{
 return refcount_dec_and_test(&block->refcnt);
}

/* must be called with prestera_counter_block_lock() */
static void prestera_counter_stats_clear(struct prestera_counter_block *block,
      u32 counter_id)
{
 memset(&block->stats[counter_id - block->offset], 0,
        sizeof(*block->stats));
}

static struct prestera_counter_block *
prestera_counter_block_lookup_not_full(struct prestera_counter *counter,
           u32 client)
{
 u32 i;

 prestera_counter_lock(counter);
 for (i = 0; i < counter->block_list_len; i++) {
  if (counter->block_list[i] &&
      counter->block_list[i]->client == client &&
      !counter->block_list[i]->full &&
      prestera_counter_block_incref(counter->block_list[i])) {
   prestera_counter_unlock(counter);
   return counter->block_list[i];
  }
 }
 prestera_counter_unlock(counter);

 return NULL;
}

static int prestera_counter_block_list_add(struct prestera_counter *counter,
        struct prestera_counter_block *block)
{
 struct prestera_counter_block **arr;
 u32 i;

 prestera_counter_lock(counter);

 for (i = 0; i < counter->block_list_len; i++) {
  if (counter->block_list[i])
   continue;

  counter->block_list[i] = block;
  prestera_counter_unlock(counter);
  return 0;
 }

 arr = krealloc(counter->block_list, (counter->block_list_len + 1) *
         sizeof(*counter->block_list), GFP_KERNEL);
 if (!arr) {
  prestera_counter_unlock(counter);
  return -ENOMEM;
 }

 counter->block_list = arr;
 counter->block_list[counter->block_list_len] = block;
 counter->block_list_len++;
 prestera_counter_unlock(counter);
 return 0;
}

static struct prestera_counter_block *
prestera_counter_block_get(struct prestera_counter *counter, u32 client)
{
 struct prestera_counter_block *block;
 int err;

 block = prestera_counter_block_lookup_not_full(counter, client);
 if (block)
  return block;

 block = kzalloc(sizeof(*block), GFP_KERNEL);
 if (!block)
  return ERR_PTR(-ENOMEM);

 err = prestera_hw_counter_block_get(counter->sw, client,
         &block->id, &block->offset,
         &block->num_counters);
 if (err)
  goto err_block;

 block->stats = kcalloc(block->num_counters,
          sizeof(*block->stats), GFP_KERNEL);
 if (!block->stats) {
  err = -ENOMEM;
  goto err_stats;
 }

 block->counter_flag = kcalloc(block->num_counters,
          sizeof(*block->counter_flag),
          GFP_KERNEL);
 if (!block->counter_flag) {
  err = -ENOMEM;
  goto err_flag;
 }

 block->client = client;
 mutex_init(&block->mtx);
 refcount_set(&block->refcnt, 1);
 idr_init_base(&block->counter_idr, block->offset);

 err = prestera_counter_block_list_add(counter, block);
 if (err)
  goto err_list_add;

 return block;

err_list_add:
 idr_destroy(&block->counter_idr);
 mutex_destroy(&block->mtx);
 kfree(block->counter_flag);
err_flag:
 kfree(block->stats);
err_stats:
 prestera_hw_counter_block_release(counter->sw, block->id);
err_block:
 kfree(block);
 return ERR_PTR(err);
}

static void prestera_counter_block_put(struct prestera_counter *counter,
           struct prestera_counter_block *block)
{
 u32 i;

 if (!prestera_counter_block_decref(block))
  return;

 prestera_counter_lock(counter);
 for (i = 0; i < counter->block_list_len; i++) {
  if (counter->block_list[i] &&
      counter->block_list[i]->id == block->id) {
   counter->block_list[i] = NULL;
   break;
  }
 }
 prestera_counter_unlock(counter);

 WARN_ON(!idr_is_empty(&block->counter_idr));

 prestera_hw_counter_block_release(counter->sw, block->id);
 idr_destroy(&block->counter_idr);
 mutex_destroy(&block->mtx);
 kfree(block->stats);
 kfree(block);
}

static int prestera_counter_get_vacant(struct prestera_counter_block *block,
           u32 *id)
{
 int free_id;

 if (block->full)
  return -ENOSPC;

 prestera_counter_block_lock(block);
 free_id = idr_alloc_cyclic(&block->counter_idr, NULL, block->offset,
       block->offset + block->num_counters,
       GFP_KERNEL);
 if (free_id < 0) {
  if (free_id == -ENOSPC)
   block->full = true;

  prestera_counter_block_unlock(block);
  return free_id;
 }
 *id = free_id;
 prestera_counter_block_unlock(block);

 return 0;
}

int prestera_counter_get(struct prestera_counter *counter, u32 client,
    struct prestera_counter_block **bl, u32 *counter_id)
{
 struct prestera_counter_block *block;
 int err;
 u32 id;

get_next_block:
 block = prestera_counter_block_get(counter, client);
 if (IS_ERR(block))
  return PTR_ERR(block);

 err = prestera_counter_get_vacant(block, &id);
 if (err) {
  prestera_counter_block_put(counter, block);

  if (err == -ENOSPC)
   goto get_next_block;

  return err;
 }

 prestera_counter_block_lock(block);
 if (block->is_updating)
  block->counter_flag[id - block->offset] = COUNTER_FLAG_INVALID;
 prestera_counter_block_unlock(block);

 *counter_id = id;
 *bl = block;

 return 0;
}

void prestera_counter_put(struct prestera_counter *counter,
     struct prestera_counter_block *block, u32 counter_id)
{
 if (!block)
  return;

 prestera_counter_block_lock(block);
 idr_remove(&block->counter_idr, counter_id);
 block->full = false;
 prestera_counter_stats_clear(block, counter_id);
 prestera_counter_block_unlock(block);

 prestera_hw_counter_clear(counter->sw, block->id, counter_id);
 prestera_counter_block_put(counter, block);
}

static u32 prestera_counter_block_idx_next(struct prestera_counter *counter,
        u32 curr_idx)
{
 u32 idx, i, start = curr_idx + 1;

 prestera_counter_lock(counter);
 for (i = 0; i < counter->block_list_len; i++) {
  idx = (start + i) % counter->block_list_len;
  if (!counter->block_list[idx])
   continue;

  prestera_counter_unlock(counter);
  return idx;
 }
 prestera_counter_unlock(counter);

 return 0;
}

static struct prestera_counter_block *
prestera_counter_block_get_by_idx(struct prestera_counter *counter, u32 idx)
{
 if (idx >= counter->block_list_len)
  return NULL;

 prestera_counter_lock(counter);

 if (!counter->block_list[idx] ||
     !prestera_counter_block_incref(counter->block_list[idx])) {
  prestera_counter_unlock(counter);
  return NULL;
 }

 prestera_counter_unlock(counter);
 return counter->block_list[idx];
}

static void prestera_counter_stats_work(struct work_struct *work)
{
 struct delayed_work *dl_work = to_delayed_work(work);
 struct prestera_counter *counter =
  container_of(dl_work, struct prestera_counter, stats_dw);
 struct prestera_counter_block *block;
 u32 resched_time = COUNTER_POLL_TIME;
 u32 count = COUNTER_BULK_SIZE;
 bool done = false;
 int err;
 u32 i;

 block = prestera_counter_block_get_by_idx(counter, counter->curr_idx);
 if (!block) {
  if (counter->is_fetching)
   goto abort;

  goto next;
 }

 if (!counter->is_fetching) {
  err = prestera_hw_counter_trigger(counter->sw, block->id);
  if (err)
   goto abort;

  prestera_counter_block_lock(block);
  block->is_updating = true;
  prestera_counter_block_unlock(block);

  counter->is_fetching = true;
  counter->total_read = 0;
  resched_time = COUNTER_RESCHED_TIME;
  goto resched;
 }

 prestera_counter_block_lock(block);
 err = prestera_hw_counters_get(counter->sw, counter->total_read,
           &count, &done,
           &block->stats[counter->total_read]);
 prestera_counter_block_unlock(block);
 if (err)
  goto abort;

 counter->total_read += count;
 if (!done || counter->total_read < block->num_counters) {
  resched_time = COUNTER_RESCHED_TIME;
  goto resched;
 }

 for (i = 0; i < block->num_counters; i++) {
  if (block->counter_flag[i] == COUNTER_FLAG_INVALID) {
   prestera_counter_block_lock(block);
   block->counter_flag[i] = COUNTER_FLAG_READY;
   memset(&block->stats[i], 0, sizeof(*block->stats));
   prestera_counter_block_unlock(block);
  }
 }

 prestera_counter_block_lock(block);
 block->is_updating = false;
 prestera_counter_block_unlock(block);

 goto next;
abort:
 prestera_hw_counter_abort(counter->sw);
next:
 counter->is_fetching = false;
 counter->curr_idx =
  prestera_counter_block_idx_next(counter, counter->curr_idx);
resched:
 if (block)
  prestera_counter_block_put(counter, block);

 schedule_delayed_work(&counter->stats_dw, resched_time);
}

/* Can be executed without rtnl_lock().
 * So pay attention when something changing.
 */
int prestera_counter_stats_get(struct prestera_counter *counter,
          struct prestera_counter_block *block,
          u32 counter_id, u64 *packets, u64 *bytes)
{
 if (!block || !prestera_counter_is_ready(block, counter_id)) {
  *packets = 0;
  *bytes = 0;
  return 0;
 }

 prestera_counter_block_lock(block);
 *packets = block->stats[counter_id - block->offset].packets;
 *bytes = block->stats[counter_id - block->offset].bytes;

 prestera_counter_stats_clear(block, counter_id);
 prestera_counter_block_unlock(block);

 return 0;
}

int prestera_counter_init(struct prestera_switch *sw)
{
 struct prestera_counter *counter;

 counter = kzalloc(sizeof(*counter), GFP_KERNEL);
 if (!counter)
  return -ENOMEM;

 counter->block_list = kzalloc(sizeof(*counter->block_list), GFP_KERNEL);
 if (!counter->block_list) {
  kfree(counter);
  return -ENOMEM;
 }

 mutex_init(&counter->mtx);
 counter->block_list_len = 1;
 counter->sw = sw;
 sw->counter = counter;

 INIT_DELAYED_WORK(&counter->stats_dw, prestera_counter_stats_work);
 schedule_delayed_work(&counter->stats_dw, COUNTER_POLL_TIME);

 return 0;
}

void prestera_counter_fini(struct prestera_switch *sw)
{
 struct prestera_counter *counter = sw->counter;
 u32 i;

 cancel_delayed_work_sync(&counter->stats_dw);

 for (i = 0; i < counter->block_list_len; i++)
  WARN_ON(counter->block_list[i]);

 mutex_destroy(&counter->mtx);
 kfree(counter->block_list);
 kfree(counter);
}